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[smooth] Reduce divisions in the line renderer.

We don't need some divisions if a line segments stays within a single
row or a single column of pixels.

* src/smooth/ftgrays.c (gray_render_line) [FT_LONG64]: Make divisions
conditional.

git/fs: mount .git/fs: mount/attach disallowed

--- a/ChangeLog

+++ b/ChangeLog

@@ -1,3 +1,13 @@

+2016-09-22  Alexei Podtelezhnikov  <[email protected]>

+

+	[smooth] Reduce divisions in the line renderer.

+

+	We don't need some divisions if a line segments stays within a single

+	row or a single column of pixels.

+

+	* src/smooth/ftgrays.c (gray_render_line) [FT_LONG64]: Make divisions

+	conditional.

+

 2016-09-15  Alexei Podtelezhnikov  <[email protected]>

 	* src/smooth/ftgrays.c (gray_sweep): Remove check for empty table.

--- a/src/smooth/ftgrays.c

+++ b/src/smooth/ftgrays.c

@@ -371,8 +371,9 @@

   /* These macros speed up repetitive divisions by replacing them */

   /* with multiplications and right shifts.                       */

-#define FT_UDIVPREP( b )                                       \

-  long  b ## _r = (long)( FT_ULONG_MAX >> PIXEL_BITS ) / ( b )

+#define FT_UDIVPREP( c, b )                                        \

+  long  b ## _r = c ? (long)( FT_ULONG_MAX >> PIXEL_BITS ) / ( b ) \

+                    : 0

 #define FT_UDIV( a, b )                                        \

   ( ( (unsigned long)( a ) * (unsigned long)( b ## _r ) ) >>   \

     ( sizeof( long ) * FT_CHAR_BIT - PIXEL_BITS ) )

@@ -890,8 +891,8 @@

     else                                  /* any other line */

     {

       TPos  prod = dx * fy1 - dy * fx1;

-      FT_UDIVPREP( dx );

-      FT_UDIVPREP( dy );

+      FT_UDIVPREP( ex1 != ex2, dx );

+      FT_UDIVPREP( ey1 != ey2, dy );

       /* The fundamental value `prod' determines which side and the  */